1. Field of the Invention
The present invention relates to recording heads and recording apparatuses using the recording heads.
2. Description of the Related Art
FIG. 9 is a block diagram illustrating an example circuit configuration of a known recording head. Heaters 401 are recording elements for generating thermal energy. Switching elements 402 are drivers for supplying desired current to the heaters. Each driver is connected to a corresponding recording element. A shift register 403 receives a data signal DATA in a serial manner on the basis of a clock signal CLK. The data signal DATA includes information on block specification and image data. The data in the shift register 403 is latched by a latch circuit 406 in synchronization with a latch signal LT.
A decoder 414 decodes the information on the block specification, and outputs signals to AND circuits 404 on the basis of the decoded results. In this manner, the recording elements to be driven at the same time are selected.
FIG. 10 is a timing chart of the signals for driving the known recording elements. The data signal DATA is transferred to the shift register 403 shown in FIG. 9 in synchronization with the clock signal CLK. The data signal DATA includes 4-bit information (B0 to B3) on the block specification and 16-bit image data (D0 to D15). Herein, sixteen recording elements constitute one block, and the 16-bit data is transferred such that each of the data components is assigned to a corresponding recording element. Further, the recording head includes sixteen blocks, and the 4-bit information (B0 to B3) is used for specifying the blocks.
When the latch signal LT is input to the latch circuit 406, the data signal DATA is held by the latch circuit 406. When a heat-enable signal HE is active (low level), the switching elements 402 can be turned on. VH and GND shown in FIG. 9 denote voltage applied to the recording elements and a ground signal, respectively.
Japanese Patent Laid-Open No. 2005-161682 describes driving of recording elements and control of a latch circuit by using both a heat-enable signal HE and a latch signal LT.
On the other hand, Japanese Patent Laid-Open No. 2000-263770 describes driving of recording elements at timings differing for each of the recording elements so as to realize an ink-jet recording apparatus with higher recording speed and higher image quality.
Not only recording apparatuses with higher recording speed and higher image quality described above, a demand for recording apparatuses with reduced noise emission is increasing. However, an additional function for reducing noise emission requires additional terminals for inputting new signals to recording heads. The additional terminals disadvantageously lead to a reduction in the reliability of wiring connections and an increase in chip area.